US4321677A - Anti-skid control device - Google Patents

Anti-skid control device Download PDF

Info

Publication number
US4321677A
US4321677A US06/118,909 US11890980A US4321677A US 4321677 A US4321677 A US 4321677A US 11890980 A US11890980 A US 11890980A US 4321677 A US4321677 A US 4321677A
Authority
US
United States
Prior art keywords
slip rate
circuit means
wheel speed
calculation circuit
brake
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US06/118,909
Other languages
English (en)
Inventor
Junichi Takahashi
Takanori Shibata
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Assigned to HITACHI, LTD. reassignment HITACHI, LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SHIBATA, TAKANORI, TAKAHASHI, JUNICHI
Application granted granted Critical
Publication of US4321677A publication Critical patent/US4321677A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/176—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS
    • B60T8/1763—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS responsive to the coefficient of friction between the wheels and the ground surface
    • B60T8/17636—Microprocessor-based systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S188/00—Brakes
    • Y10S188/01—Panic braking

Definitions

  • This invention relates to an anti-skid control device and, more particularly, to an anti-skid control device incorporating a microcomputer for controlling a skid.
  • Such anti-skid control device is for the purpose of automatically releasing a braking force applied to wheels of a vehicle during braking operations to prevent wheel locking and thus to insure a safe braking operation.
  • an automobile is steerable due to friction between road surfaces and wheels, and can run safely as long as a frictional force, or a clinging force, of the wheels is maintained at a suitable value.
  • a frictional force, or a clinging force, of the wheels is maintained at a suitable value.
  • a force exceeding the clinging force of the wheels acts on the automobile, the wheel or wheels slip on the road surface preventing a normal running of the automobile and causes abnormal running conditions. This condition is generally referred to as "skid".
  • the skid is affected by various factors.
  • One of these factors is a speed of the automobile.
  • a high automobile speed tends to cause a spin of the automobile even at a small steering angle. Abrupt increases in a yawing angle velocity and in a slip angle of rear wheels are observed in a state of spinning.
  • the skid condition is also affected by a frictional coefficient of the road surface. For instance, comparing a concrete road surface (frictional coefficient 0.8) with a wet road surface (frictional coefficient 0.4), the spin takes place at a smaller steering angle in the case of the road surface with a small frictional coefficient, i.e. the wet road surface, than in the case of the road surface with a higher frictional coefficient.
  • a typical and conventional anti-skid controlling method is to compare a wheel speed with a estimated vehicle velocity by using a comparator and to control the brake release valve successively by the output of the comparator.
  • the device of the prior art for an anti-skid control device has had the disadvantage that a considerably long time lag is observed for the anti-skid control because it is time consuming to perform a continuous calculation of slip ratio from wheel velocity and estimated vehicle velocity to determine the timing of the brake releasing operation.
  • An object of this invention is to provide an anti-skid control device which is capable of controlling a skid with an optimum braking in the occurrence of skid by panic braking.
  • Another object of this invention is to provide an anti-skid control device which is capable of controlling a skid quickly.
  • Still another object of this invention is to provide an anti-skid control device which is capable of controlling a skid based on the condition of road surfaces.
  • a further object of this invention is to provide an anti-skid control device which is capable of controlling a skid effectively.
  • At least one skid control pattern corresponding to a slip rate previously obtained through experiments is memorized beforehand in a memory so that an anti-skid control is made in accordance with the controlling pattern corresponding to the rate of slip actually taking place.
  • FIG. 1 is a block diagram of an embodiment of the invention
  • FIG. 2 is a chart showing the relation between the slip rate and the frictional coefficient
  • FIG. 3 is a chart showing the relation between the automobile speed and the wheel speed
  • FIG. 4 is a chart showing the attenuation of the automobile speed as observed when the wheels of the automobile are locked due to a panic braking on roads for different slip rates;
  • FIGS. 5 and 6 are flow charts of the anti-skid control made in accordance with the described embodiment of the invention.
  • an anti-skid control device embodying the present invention comprises a control circuit, a wheel speed detector 19, a hydraulic brake system 71 of a vehicle, and an alarm circuit 18.
  • a control circuit comprises a microcomputer 20 and an input/output port 14 (hereinafter referred to as I/O).
  • a microcomputer 20 comprises a microprocessing unit 11 (hereinafter referred to as MPU), a read only memory 12 (hereinafter referred to as ROM), a random access memory 13 (hereinafter referred to as RAM), and a bus line 15.
  • the RAM 13 contains the resetable memory for event counting.
  • the MPU 11 contains the resettable register for calculation.
  • the hydraulic brake system 71 comprises a solenoid 16 and an actuator 17.
  • the MPU 11 is adapted to perform various functions such as execution of instructions in accordance with the programs written in ROM 12, storing data in the RAM 13 for a temporary memorization for these data, and inputs and outputs of required signals.
  • the I/O 14 is adapted to receive signals derived from the wheel speed detector 19 and to deliver the signals such as an anti-skid control signal to the hydraulic brake system 71 of the vehicle, and a fail-safe signal to the alarm circuit 18.
  • V is defined as a following formula (1).
  • R the radius of the tire
  • ⁇ the angular velocity of the tire.
  • the slip rate S is defined as follows.
  • FIG. 2 is a chart showing the relation between the slip rate S and the friction coefficient ⁇ between the tire and the road surface.
  • the frictional coefficient ⁇ is shown as a function of slip rate S.
  • the frictional coefficient in the progress direction of a vehicle indicates the maximum value at the point nearly 20% slip rate, and the frictional coefficient in the transverse direction of a vehicle decreases in proportion as the slip rate S increases.
  • a and A' denote the characteristic curves in the case of a concrete road
  • B and B' denote the characteristic curves in the case of a snowy road.
  • the controlling of a vehicle to have a slip rate 20% makes the frictional coefficient ⁇ between the tire and the road surface maximum in the state of skid.
  • the anti-skid control device controls the slip rate S to be 20%.
  • vehicle weight W is deemed as follows.
  • deceleration velocity dV/dt of vehicle in the case of braking is represented as "-g".
  • slip rate S shown by formula (3) can be calculated by putting "-g" in the place of vehicle velocity therein.
  • the present invention can be summed up as follows:
  • Slip rate S can be calculated by regarding the estimated vehicle velocity "-g" as the vehicle velocity
  • Hydraulic brake system of the vehicle controls the brake oil pressure so that the slip rate S of the vehicle becomes approximately 20% by the instruction of the computer 20 through the I/O 14.
  • FIG. 3 is a chart showing the relation among the actual vehicle velocity, the estimated vehicle velocity, the wheel velocity, and an increase (ON) or a decrease (OFF) signal of the brake oil pressure in the case of brake oil pressure being controlled by the actuator 17 so that the frictional coefficient between the wheel and the road surfaces becomes maximum.
  • the vehicle velocity is deemed to be substantially equal to the estimated vehicle velocity in principle.
  • the estimated vehicle velocity is compared with the curve C or D in order to obtain the slip rate according to the formula (3).
  • the time chart C' and D' denote the wave forms of the output signal produced when the wheel velocity changes as shown at C and D, respectively.
  • the anti-skid control device of the present invention When the slip rate becomes the appointed slip rate 50%, the anti-skid control device of the present invention outputs the brake release signal "OFF" as shown at the time chart C' or D'.
  • the wheel velocity becomes again faster than the velocity at the time that the output signal C' or D' has been turned off.
  • the anti-skid control device of the present invention When the slip rate becomes 20%, the anti-skid control device of the present invention outputs the brake signal "ON" as shown at the time chart C' or D'.
  • the time duration t ON of the brake release signal changes in accordance with the value of the frictional coefficient.
  • the timing of the present invention is as follows.
  • the ROM 12 holds the value of the estimated vehicle velocity at the time that the output signal C' or D' has turned off.
  • the MPU 11 compares the estimated vehicle velocity with the actual wheel velocity after the output signal C' or D' has been turned off, and calculates the slip rate.
  • the MPU 11 outputs the brake signal "ON" when the slip rate reaches the predetermined 20% slip rate.
  • FIG. 4 shows characteristic curves which represent the deceleration of an automobile or a vehicle with its wheel locked due to a panic braking on various roads of different slip rates.
  • the characteristic curve S 1 shows the deceleration of an automobile with its wheels locked due to a panic braking on an icy road or a road having an equivalent frictional coefficient.
  • the characteristic curves S 3 and S 4 represent the state of deceleration of the automobile with its wheels locked due to a panic braking on a wet asphalt road or road having an equivalent frictional coefficient and dried concrete road or road having an equivalent frictional coefficient, respectively.
  • the automobile can be stopped in a comparatively short distance when on the dry concrete road, but runs a considerably long distance before it is stopped when on the icy road.
  • G acceleration of gravity
  • the wheel speed detector 19 detects the wheel speed intermittently at a constant time interval or an interval varied in accordance with the wheel velocity.
  • the output from this detector 19 is stored in the RAM 13 through the I/O 14.
  • the MPU 11 judges the skid is taking place.
  • the control after this judgement made by the MPU 11 varies depending on the program of the ROM 12.
  • the skid is controlled irrespective of the actual road condition, in accordance with a typical or representative single control characteristic curve S 2 shown in FIG. 4 which is optimum for the anti-skid control on the imaginary road surface.
  • the microcomputer 20 controls the hydraulic brake system of the vehicle 7 in such a manner that the wheel velocity is decreased so as to follow the curve as shown in FIG. 3.
  • the slip rate is calculated from the wheel speeds which are picked up successively.
  • a plurality of automobile speed attenuation characteristic curves corresponding to a plurality of frictional coefficients are stored beforehand in the ROM 12, and a speed attenuation characteristic corresponding to the calculated slip rate is selected.
  • the speed attenuation characteristic corresponds to the estimated vehicle velocity in FIG. 3. Then, the hydraulic brake system of the vehicle 71 is operated to effect an anti-skid control in accordance with the selected automobile speed attenuation characteristic.
  • the MPU 11 continuously calculates the slip rate from the wheel speeds which are detected successively and selects one of the attenuation curves for different road conditions stored in the ROM 12, to which the calculated slip rate corresponds. Then, the slip rate S of the automobile is determined from the relationship between the attenuation characteristic curves shown in FIG. 4 and the detected wheel speed. The solenoid 16 is then operated through the I/O 14 to actuate the actuator 17 thereby to control the brake in such a manner as to provide the maximum frictional coefficient.
  • FIG. 5, and FIG. 6 show the flow chart of the anti-skid control of the present invention.
  • the microcomputer 20 initializes all the registers, or resetable memory and register at the RAM 13 and the MPU 11, respectively, at the step 50 by the instruction of a start signal of the automobile.
  • the microcomputer 20 self-checks the functions of the control circuits, especially, the ROM 12, the RAM 13, and the I/O 14.
  • the MPU 11 gives the specific patterns to the control circuits so as to check the control circuits.
  • the control circuits output the reply signals corresponding to the specific patterns, the control circuits are judged to be in normal condition by the MPU 11. If an abnormal condition is detected at the step 51 of self-check, it is announced to the alarm circuit 18 at the step 53.
  • control circuit is self-checked whether it is in normal condition or not, predetermined N times at the step 54. If an abnormal condition is not removed after N times check 54, it is anounced by the alarm lamp in the alarm circuit 18, and the anti-skid control device is stopped at the step of 55.
  • the program of the ROM 12 advances to the step 56.
  • the register of I/O 14 stores the values of the wheel speed through the wheel speed detector 19.
  • the MPU 11 calculates the wheel velocity by referring to the memory of the I/O 14.
  • the MPU 11 judges whether the panic braking occurs by referring to the variation of the wheel speed.
  • the program of the ROM 12 advances to the step 56 and the MPU 11 calculates the wheel velocity.
  • the microcomputer 20 repeats the calculation of the wheel speed within the loop of steps 56 and 57.
  • the program of the ROM 12 advances to the step 58.
  • the slip rate S is calculated. And the speed attenuation characteristics corresponding to the calculated slip rate are selected.
  • the MPU 11 judges whether the slip rate reaches the predetermined value, that is, 50% slip rate or 20% slip rate. When the slip rate becomes 50%, the microcomputer 20 outputs the brake release signal at the step 61. After the output of the brake release signal, the program of the ROM 12 advances to the step 56. When the slip rate becomes 20%, the microcomputer 20 checks whether the actuator 17 is ON or OFF. When the MPU 11 judges the actuator 17 is OFF, the program of the ROM 12 advances to the step 56.
  • the program of the ROM 12 advances to the step 65.
  • the brake release signal is cut off.
  • the microcomputer 20 measures "ON TIME" (the time interval of the brake release signal).
  • the slip rate which is necessary for the next brake releasing timing is calculated, and it is stored in the ROM 12. After the step 75, the program advances the step to that of 56.
  • the skid which takes place when the automobile is braked abruptly is controlled to provide the optimum braking condition.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Regulating Braking Force (AREA)
US06/118,909 1979-02-16 1980-02-06 Anti-skid control device Expired - Lifetime US4321677A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP54-16128 1979-02-16
JP1612879A JPS55110648A (en) 1979-02-16 1979-02-16 Skid control device by use of microcomputer

Publications (1)

Publication Number Publication Date
US4321677A true US4321677A (en) 1982-03-23

Family

ID=11907852

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/118,909 Expired - Lifetime US4321677A (en) 1979-02-16 1980-02-06 Anti-skid control device

Country Status (4)

Country Link
US (1) US4321677A (enrdf_load_stackoverflow)
JP (1) JPS55110648A (enrdf_load_stackoverflow)
DE (1) DE3005572A1 (enrdf_load_stackoverflow)
GB (1) GB2042661B (enrdf_load_stackoverflow)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4398260A (en) * 1979-05-18 1983-08-09 Hitachi, Ltd. Skid control method
US4538228A (en) * 1982-02-18 1985-08-27 Knorr-Bremse Gmbh Hydraulic pressure actuated brake system for rail vehicles
US4545240A (en) * 1981-05-14 1985-10-08 Robert Bosch Gmbh Apparatus for ascertaining the adhesion factor of a road surface
US4700304A (en) * 1983-12-31 1987-10-13 Pcb Controls Public Limited Company Electronic control unit for an anti-skid braking system
US4709194A (en) * 1985-09-20 1987-11-24 Mitsubishi Denki Kabushiki Kaisha Method of controlling the mode of driving electric vehicles
US4933858A (en) * 1983-05-17 1990-06-12 Nissan Motor Company, Limited Anti-skid brake control system for an automotive brake system having variable deceleration threshold
US4999778A (en) * 1987-12-05 1991-03-12 Daimler-Benz Ag Method and apparatus for determining slip thresholds for a propulsion slip control system of a motor vehicle
US5123715A (en) * 1990-02-16 1992-06-23 Akebono Brake Industry Co., Ltd. Estimating road friction coefficient
US20030011243A1 (en) * 2000-02-14 2003-01-16 Hakan Andersson Arrangement for ensuring the function of a vehicle brake
EP1084922A3 (en) * 1999-09-20 2003-07-23 Westinghouse Air Brake Company Brake system for a railway freight train
US6623090B2 (en) * 2000-06-30 2003-09-23 Robert Bosch Gmbh Method and device for detecting a panic braking operation
US20050140322A1 (en) * 2002-04-11 2005-06-30 Yusuke Itakura Vehicle capable of changing vehicle characteristics

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0213270Y2 (enrdf_load_stackoverflow) * 1981-03-12 1990-04-12
JPS5957053A (ja) * 1982-09-25 1984-04-02 Mitsubishi Electric Corp 列車減速度制御装置
JPS59209942A (ja) * 1983-05-16 1984-11-28 Nissan Motor Co Ltd アンチスキツド制御装置
JPH02107862A (ja) * 1988-10-17 1990-04-19 Iseki & Co Ltd 走行車両の変速装置
US20090187324A1 (en) 2008-01-23 2009-07-23 Jianbo Lu Vehicle Stability Control System and Method
CN105346708B (zh) * 2015-11-10 2017-05-10 西安航空制动科技有限公司 一种轮胎与地面最佳刹车滑移点的确定方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3653727A (en) * 1968-10-22 1972-04-04 Otto Gosta Kullberg Brake control system for wheeled vehicles
US3807811A (en) * 1970-09-11 1974-04-30 Nippon Denso Co Anti-skid control system for vehicles
US3912337A (en) * 1971-07-06 1975-10-14 Toyota Motor Co Ltd Antiskid apparatus
US3985396A (en) * 1972-07-20 1976-10-12 Aisin Seiki Kabushiki Kaisha Method, circuit, and apparatus for anti-skid brake control in motor vehicles
US4006942A (en) * 1973-09-14 1977-02-08 Masashi Saito Antilock system for wheeled vehicles
US4094556A (en) * 1968-04-24 1978-06-13 Nippondenso Kabushiki Kaisha Anti-skid system for a vehicle
US4157850A (en) * 1976-10-04 1979-06-12 Societe Anonyme D.B.A. Electronic antiskid control device
US4184203A (en) * 1978-10-20 1980-01-15 Crane Co. Wheel speed sensing system

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4094556A (en) * 1968-04-24 1978-06-13 Nippondenso Kabushiki Kaisha Anti-skid system for a vehicle
US3653727A (en) * 1968-10-22 1972-04-04 Otto Gosta Kullberg Brake control system for wheeled vehicles
US3807811A (en) * 1970-09-11 1974-04-30 Nippon Denso Co Anti-skid control system for vehicles
US3912337A (en) * 1971-07-06 1975-10-14 Toyota Motor Co Ltd Antiskid apparatus
US3985396A (en) * 1972-07-20 1976-10-12 Aisin Seiki Kabushiki Kaisha Method, circuit, and apparatus for anti-skid brake control in motor vehicles
US4006942A (en) * 1973-09-14 1977-02-08 Masashi Saito Antilock system for wheeled vehicles
US4157850A (en) * 1976-10-04 1979-06-12 Societe Anonyme D.B.A. Electronic antiskid control device
US4184203A (en) * 1978-10-20 1980-01-15 Crane Co. Wheel speed sensing system

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4398260A (en) * 1979-05-18 1983-08-09 Hitachi, Ltd. Skid control method
US4545240A (en) * 1981-05-14 1985-10-08 Robert Bosch Gmbh Apparatus for ascertaining the adhesion factor of a road surface
US4538228A (en) * 1982-02-18 1985-08-27 Knorr-Bremse Gmbh Hydraulic pressure actuated brake system for rail vehicles
US4933858A (en) * 1983-05-17 1990-06-12 Nissan Motor Company, Limited Anti-skid brake control system for an automotive brake system having variable deceleration threshold
US4700304A (en) * 1983-12-31 1987-10-13 Pcb Controls Public Limited Company Electronic control unit for an anti-skid braking system
US4709194A (en) * 1985-09-20 1987-11-24 Mitsubishi Denki Kabushiki Kaisha Method of controlling the mode of driving electric vehicles
US4999778A (en) * 1987-12-05 1991-03-12 Daimler-Benz Ag Method and apparatus for determining slip thresholds for a propulsion slip control system of a motor vehicle
US5123715A (en) * 1990-02-16 1992-06-23 Akebono Brake Industry Co., Ltd. Estimating road friction coefficient
EP1084922A3 (en) * 1999-09-20 2003-07-23 Westinghouse Air Brake Company Brake system for a railway freight train
US20030011243A1 (en) * 2000-02-14 2003-01-16 Hakan Andersson Arrangement for ensuring the function of a vehicle brake
US6923512B2 (en) * 2000-02-14 2005-08-02 Scania Cv Ab (Publ) Arrangement for ensuring the function of a vehicle brake
US6623090B2 (en) * 2000-06-30 2003-09-23 Robert Bosch Gmbh Method and device for detecting a panic braking operation
US20050140322A1 (en) * 2002-04-11 2005-06-30 Yusuke Itakura Vehicle capable of changing vehicle characteristics

Also Published As

Publication number Publication date
JPS55110648A (en) 1980-08-26
DE3005572A1 (de) 1980-08-21
GB2042661B (en) 1983-02-16
GB2042661A (en) 1980-09-24
JPS6216856B2 (enrdf_load_stackoverflow) 1987-04-15

Similar Documents

Publication Publication Date Title
US4321677A (en) Anti-skid control device
US4664453A (en) Anti-lock brake control system
US4755945A (en) Adaptive mode anti-lock brake controller
US6952637B2 (en) Rough road detection using suspension system information
US4673226A (en) Vehicle skid control system
EP0958978B1 (en) Vehicle yaw control method
US4761741A (en) Anti-lock brake control system
EP0219238B1 (en) Anti-lock brake control apparatusand method
US4673225A (en) Anti-lock brake control system
US6882921B2 (en) Traction control algorithm for vehicle operation upon deformable road surfaces
US4783127A (en) Anti-lock brake control system
US5173860A (en) Reference speed determination for an antilock brake system
US5865514A (en) Circuit arrangement for a braking system with anti-lock control system
US5707121A (en) Anti-lock braking systems (ABS) for road vehicles to avoid premature engagement of the anti-lock braking system
KR970007719B1 (ko) 차량견인 제어시스템
US4807134A (en) DC torque motor actuated anti-lock brake controller
USRE33663E (en) DC torque motor actuated anti-lock brake controller
US6212461B1 (en) Extended brake switch software for vehicle stability enhancement system
CA1252181A (en) Antiskid control system responsive to road surface reaction
US5551769A (en) Method and system for split mu control for anti-lock brake systems
JPH06503525A (ja) アンチロック・ブレーキ調整システム
US4308583A (en) Anti-skid device for a motor vehicle braking system
JPH0729599B2 (ja) アンチスキツド制御方法
USRE33557E (en) Anti-lock brake control system
JPH08207544A (ja) 駆動車軸重付加装置

Legal Events

Date Code Title Description
AS Assignment

Owner name: HITACHI, LTD., 5-1, 1-CHOME, MARUNOUCHI, CHIYODA-K

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:TAKAHASHI, JUNICHI;SHIBATA, TAKANORI;REEL/FRAME:003906/0951

Effective date: 19800121

STCF Information on status: patent grant

Free format text: PATENTED CASE